CHEM1. (JAN13CHEM101) WMP/Jan13/CHEM1. General Certificate of Education Advanced Subsidiary Examination January Unit 1 Foundation Chemistry

Transcription

1 Centre Number Surname Candidate Number For Examiner s Use Other Names Candidate Signature Examiner s Initials General Certificate of Education Advanced Subsidiary Examination January 2013 Question 1 2 Mark Chemistry Unit 1 Foundation Chemistry Thursday 10 January am to am For this paper you must have: l l the Periodic Table/Data Sheet, provided as an insert (enclosed) a calculator. CEM TOTAL Time allowed l 1 hour 15 minutes Instructions l Use black ink or black ball-point pen. l Fill in the es at the top of this page. l Answer all questions. l You must answer the questions in the spaces provided. around each page or on blank pages. l All working must be shown. l Do all rough work in this book. Cross through any work you do not want to be marked. Information l The marks for questions are shown in brackets. l The maximum mark for this paper is 70. l You are expected to use a calculator, where appropriate. l The Periodic Table/Data Sheet is provided as an insert. l Your answers to the questions in Section B should be written in continuous prose, where appropriate. l You will be marked on your ability to: use good English organise information clearly use scientific terminology accurately. Advice l You are advised to spend about 50 minutes on Section A and about 25 minutes on Section B. (JAN13CEM101) WMP/Jan13/CEM1 CEM1

2 2 Section A Answer all questions in the spaces provided. 1 (a) State the meaning of the term mass number of an isotope. 1 (b) Give the symbol of the element that has an isotope with a mass number of 68 and has 38 neutrons in its nucleus. 1 (c) The following shows a simplified diagram of a mass spectrometer. To vacuum pump Q Sample Detector P 1 (c) (i) State what happens to the sample in the parts labelled P and Q. P... Q... (02) WMP/Jan13/CEM1

3 3 1 (c) (ii) In a mass spectrometer, the isotopes of an element are separated. Two measurements for each isotope are recorded on the mass spectrum. State the two measurements that are recorded for each isotope. Measurement 1... Measurement (d) A sample of element R contains isotopes with mass numbers of 206, 207 and 208 in a 1:1:2 ratio of abundance. 1 (d) (i) Calculate the relative atomic mass of R. Give your answer to one decimal place. 1 (d) (ii) Identify R. (3 marks) 1 (d) (iii) All the isotopes of R react in the same way with concentrated nitric acid. State why isotopes of an element have the same chemical properties. 11 Turn over (03) WMP/Jan13/CEM1

4 4 2 (a) Use your knowledge of electron configuration and ionisation energies to answer this question. The following diagram shows the second ionisation energies of some Period 3 elements. Second ionisation energy / kj mol 1 X X X X Mg Al Si P S 2 (a) (i) Draw an X on the diagram to show the second ionisation energy of sulfur. 2 (a) (ii) Write the full electron configuration of the Al 2+ ion. 2 (a) (iii) Write an equation to show the process that occurs when the second ionisation energy of aluminium is measured. 2 (a) (iv) Give one reason why the second ionisation energy of silicon is lower than the second ionisation energy of aluminium. (04) WMP/Jan13/CEM1

5 5 2 (b) Predict the element in Period 3 that has the highest second ionisation energy. Give a reason for your answer. Element... Reason... 2 (c) The following table gives the successive ionisation energies of an element in Period 3. First Second Third Fourth Fifth Sixth Ionisation energy /kjmol Identify this element. 2 (d) Explain why the ionisation energy of every element is endothermic. 8 Turn over (05) WMP/Jan13/CEM1

6 6 3 The following table shows the electronegativity values of the elements from lithium to fluorine. Li Be B C N O F Electronegativity (a) (i) State the meaning of the term electronegativity. 3 (a) (ii) Suggest why the electronegativity of the elements increases from lithium to fluorine. 3 (b) State the type of bonding in lithium fluoride. Explain why a lot of energy is needed to melt a sample of solid lithium fluoride. Bonding... Explanation... (3 marks) (06) WMP/Jan13/CEM1

7 7 3 (c) Deduce why the bonding in nitrogen oxide is covalent rather than ionic. 3 (d) Oxygen forms several different compounds with fluorine. 3 (d) (i) Suggest the type of crystal shown by OF 2 3 (d) (ii) Write an equation to show how OF 2 reacts with steam to form oxygen and hydrogen fluoride. 3 (d) (iii) One of these compounds of oxygen and fluorine has a relative molecular mass of 70.0 and contains 54.3% by mass of fluorine. Calculate the empirical formula and the molecular formula of this compound. Show your working. Empirical formula... Molecular formula... (4 marks) 14 Turn over (07) WMP/Jan13/CEM1

8 8 4 The following table shows the boiling points of some straight-chain alkanes. C 4 C 2 6 C 3 8 C 4 10 C 5 12 Boiling point / ºC (a) State a process used to separate an alkane from a mixture of these alkanes. 4 (b) Both C 3 8 and C 4 10 can be liquefied and used as fuels for camping stoves. Suggest, with a reason, which of these two fuels is liquefied more easily. 4 (c) Write an equation for the complete combustion of C (d) Explain why the complete combustion of C 4 10 may contribute to environmental problems. 4 (e) Balance the following equation that shows how butane is used to make the compound called maleic anhydride....c 3 C 2 C 2 C O 2...C 2 2 (CO) 2 O O (08) WMP/Jan13/CEM1

9 9 4 (f) Ethanethiol (C 2 5 S), a compound with an unpleasant smell, is added to gas to enable leaks from gas pipes to be more easily detected. 4 (f) (i) Write an equation for the combustion of ethanethiol to form carbon dioxide, water and sulfur dioxide (f) (ii) Identify a compound that is used to react with the sulfur dioxide in the products of combustion before they enter the atmosphere. Give one reason why this compound reacts with sulfur dioxide. Substance... Reason... 4 (f) (iii) Ethanethiol and ethanol molecules have similar shapes. Explain why ethanol has the higher boiling point. Question 4 continues on the next page Turn over (09) WMP/Jan13/CEM1

10 10 4 (g) The following compound X is an isomer of one of the alkanes in the table on page 8. C C C C C 4 (g) (i) Give the IUPAC name of X (g) (ii) X has a boiling point of 9.5 ºC. Explain why the boiling point of X is lower than that of its straight-chain isomer. 4 (g) (iii) The following compound Y is produced when X reacts with chlorine. Cl C Cl C C C C Deduce how many other position isomers of Y can be formed. Write the number of other position isomers in this. (10) WMP/Jan13/CEM1

11 11 4 (h) Cracking of one molecule of an alkane Z produces one molecule of ethane, one molecule of propene and two molecules of ethene. 4 (h) (i) Deduce the molecular formula of Z. 4 (h) (ii) State the type of cracking that produces a high proportion of ethene and propene. Give the two conditions for this cracking process. Type of cracking... Conditions Turn over for the next question Turn over (11) WMP/Jan13/CEM1

12 12 Section B Answer all questions in the spaces provided. 5 Ammonia is used to make nitric acid (NO 3 ) by the Ostwald Process. Three reactions occur in this process. Reaction 1 4N 3 (g) + 5O 2 (g) 4NO(g) O(g) Reaction 2 2NO(g) + O 2 (g) 2NO 2 (g) Reaction 3 3NO 2 (g) + 2 O(I) 2NO 3 (aq) + NO(g) 5 (a) In one production run, the gases formed in Reaction 1 occupied a total volume of 4.31 m 3 at 25 ºC and 100 kpa. Calculate the amount, in moles, of NO produced. Give your answer to 3 significant figures. (The gas constant R = 8.31 J K 1 mol 1 ) (4 marks) (12) WMP/Jan13/CEM1

13 13 5 (b) In another production run, 3.00 kg of ammonia gas were used in Reaction 1 and all of the NO gas produced was used to make NO 2 gas in Reaction 2. 5 (b) (i) Calculate the amount, in moles, of ammonia in 3.00 kg. 5 (b) (ii) Calculate the mass of NO 2 formed from 3.00 kg of ammonia in Reaction 2 assuming an 80.0% yield. Give your answer in kilograms. (If you have been unable to calculate an answer for part (b) (i), you may assume a value of 163 mol. This is not the correct answer.) (3 marks) Question 5 continues on the next page Turn over (13) WMP/Jan13/CEM1

14 14 5 (c) Consider Reaction 3 in this process. 3NO 2 (g) + 2 O(I) 2NO 3 (aq) + NO(g) Calculate the concentration of nitric acid produced when mol of NO 2 is reacted with water and the solution is made up to 250 cm 3. 5 (d) Suggest why a leak of NO 2 gas from the Ostwald Process will cause atmospheric pollution. 5 (e) Give one reason why excess air is used in the Ostwald Process. 5 (f) Ammonia reacts with nitric acid as shown in this equation. N 3 + NO 3 N 4 NO 3 Deduce the type of reaction occurring. 14 (14) WMP/Jan13/CEM1

15 15 6 Chlorine can form molecules and ions that contain only chlorine, or that contain chlorine combined with another element. 6 (a) Use your understanding of the electron pair repulsion theory to draw the shape of the AsCl 3 molecule and the shape of the Cl 3 + ion. Include any lone pairs of electrons that influence the shape. Name the shape made by the atoms in the AsCl 3 molecule and in the Cl 3 + ion. (4 marks) 6 (b) Explain why the AsCl 4 + ion has a bond angle of 109.5º 6 END OF QUESTIONS (15) WMP/Jan13/CEM1

16 16 There are no questions printed on this page DO NOT WRITE ON TIS PAGE ANSWER IN TE SPACES PROVIDED Copyright 2013 AQA and its licensors. All rights reserved. (16) WMP/Jan13/CEM1